﻿/*--------------------------------------------------------------------------
* DynamicJson
* ver 1.2.0.0 (May. 21th, 2010)
*
* created and maintained by neuecc <ils@neue.cc>
* licensed under Microsoft Public License(Ms-PL)
* http://neue.cc/
* http://dynamicjson.codeplex.com/
*--------------------------------------------------------------------------*/
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Dynamic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization.Json;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace Twitch.Utility
{
	public class DynamicJson : DynamicObject
	{
		private enum JsonType
		{
			@string, number, boolean, @object, array, @null
		}

		// public static methods

		/// <summary>from JsonSring to DynamicJson</summary>
		public static dynamic Parse(string json)
		{
			return Parse(json, Encoding.Unicode);
		}

		/// <summary>from JsonSring to DynamicJson</summary>
		public static dynamic Parse(string json, Encoding encoding)
		{
			using (var reader = JsonReaderWriterFactory.CreateJsonReader(encoding.GetBytes(json), XmlDictionaryReaderQuotas.Max))
			{
				return ToValue(XElement.Load(reader));
			}
		}

		/// <summary>from JsonSringStream to DynamicJson</summary>
		public static dynamic Parse(Stream stream)
		{
			using (var reader = JsonReaderWriterFactory.CreateJsonReader(stream, XmlDictionaryReaderQuotas.Max))
			{
				return ToValue(XElement.Load(reader));
			}
		}

		/// <summary>from JsonSringStream to DynamicJson</summary>
		public static dynamic Parse(Stream stream, Encoding encoding)
		{
			using (var reader = JsonReaderWriterFactory.CreateJsonReader(stream, encoding, XmlDictionaryReaderQuotas.Max, _ =>
			{
			}))
			{
				return ToValue(XElement.Load(reader));
			}
		}

		/// <summary>create JsonSring from primitive or IEnumerable or Object({public property name:property value})</summary>
		public static string Serialize(object obj)
		{
			return CreateJsonString(new XStreamingElement("root", CreateTypeAttr(GetJsonType(obj)), CreateJsonNode(obj)));
		}

		// private static methods

		private static dynamic ToValue(XElement element)
		{
			var type = (JsonType)Enum.Parse(typeof(JsonType), element.Attribute("type").Value);
			switch (type)
			{
				case JsonType.boolean:
					return (bool)element;
				case JsonType.number:
					return (double)element;
				case JsonType.@string:
					return (string)element;
				case JsonType.@object:
				case JsonType.array:
					return new DynamicJson(element, type);
				case JsonType.@null:
				default:
					return null;
			}
		}

		private static JsonType GetJsonType(object obj)
		{
			if (obj == null) return JsonType.@null;

			switch (Type.GetTypeCode(obj.GetType()))
			{
				case TypeCode.Boolean:
					return JsonType.boolean;
				case TypeCode.String:
				case TypeCode.Char:
				case TypeCode.DateTime:
					return JsonType.@string;
				case TypeCode.Int16:
				case TypeCode.Int32:
				case TypeCode.Int64:
				case TypeCode.UInt16:
				case TypeCode.UInt32:
				case TypeCode.UInt64:
				case TypeCode.Single:
				case TypeCode.Double:
				case TypeCode.Decimal:
				case TypeCode.SByte:
				case TypeCode.Byte:
					return JsonType.number;
				case TypeCode.Object:
					return (obj is IEnumerable) ? JsonType.array : JsonType.@object;
				case TypeCode.DBNull:
				case TypeCode.Empty:
				default:
					return JsonType.@null;
			}
		}

		private static XAttribute CreateTypeAttr(JsonType type)
		{
			return new XAttribute("type", type.ToString());
		}

		private static object CreateJsonNode(object obj)
		{
			var type = GetJsonType(obj);
			switch (type)
			{
				case JsonType.@string:
				case JsonType.number:
					return obj;
				case JsonType.boolean:
					return obj.ToString().ToLower();
				case JsonType.@object:
					return CreateXObject(obj);
				case JsonType.array:
					return CreateXArray(obj as IEnumerable);
				case JsonType.@null:
				default:
					return null;
			}
		}

		private static IEnumerable<XStreamingElement> CreateXArray<T>(T obj) where T : IEnumerable
		{
			return obj.Cast<object>()
				.Select(o => new XStreamingElement("item", CreateTypeAttr(GetJsonType(o)), CreateJsonNode(o)));
		}

		private static IEnumerable<XStreamingElement> CreateXObject(object obj)
		{
			return obj.GetType()
				.GetProperties(BindingFlags.Public | BindingFlags.Instance)
				.Select(pi => new
				{
					Name = pi.Name,
					Value = pi.GetValue(obj, null)
				})
				.Select(a => new XStreamingElement(a.Name, CreateTypeAttr(GetJsonType(a.Value)), CreateJsonNode(a.Value)));
		}

		private static string CreateJsonString(XStreamingElement element)
		{
			using (var ms = new MemoryStream())
			using (var writer = JsonReaderWriterFactory.CreateJsonWriter(ms, Encoding.Unicode))
			{
				element.WriteTo(writer);
				writer.Flush();
				return Encoding.Unicode.GetString(ms.ToArray());
			}
		}

		// dynamic structure represents JavaScript Object/Array

		readonly XElement xml;
		readonly JsonType jsonType;

		/// <summary>create blank JSObject</summary>
		public DynamicJson()
		{
			xml = new XElement("root", CreateTypeAttr(JsonType.@object));
			jsonType = JsonType.@object;
		}

		private DynamicJson(XElement element, JsonType type)
		{
			Debug.Assert(type == JsonType.array || type == JsonType.@object);

			xml = element;
			jsonType = type;
		}

		public bool IsObject
		{
			get
			{
				return jsonType == JsonType.@object;
			}
		}

		public bool IsArray
		{
			get
			{
				return jsonType == JsonType.array;
			}
		}

		/// <summary>has property or not</summary>
		public bool IsDefined(string name)
		{
			return IsObject && (xml.Element(name) != null);
		}

		/// <summary>has property or not</summary>
		public bool IsDefined(int index)
		{
			return IsArray && (xml.Elements().ElementAtOrDefault(index) != null);
		}

		/// <summary>delete property</summary>
		public bool Delete(string name)
		{
			var elem = xml.Element(name);
			if (elem != null)
			{
				elem.Remove();
				return true;
			}
			else return false;
		}

		/// <summary>delete property</summary>
		public bool Delete(int index)
		{
			var elem = xml.Elements().ElementAtOrDefault(index);
			if (elem != null)
			{
				elem.Remove();
				return true;
			}
			else return false;
		}

		/// <summary>mapping to Array or Class by Public PropertyName</summary>
		public T Deserialize<T>()
		{
			return (T)Deserialize(typeof(T));
		}

		private object Deserialize(Type type)
		{
			return (IsArray) ? DeserializeArray(type) : DeserializeObject(type);
		}

		private dynamic DeserializeValue(XElement element, Type elementType)
		{
			var value = ToValue(element);
			if (value is DynamicJson)
			{
				value = ((DynamicJson)value).Deserialize(elementType);
			}
			return Convert.ChangeType(value, elementType);
		}

		private object DeserializeObject(Type targetType)
		{
			var result = Activator.CreateInstance(targetType);
			var dict = targetType.GetProperties(BindingFlags.Public | BindingFlags.Instance)
				.Where(p => p.CanWrite)
				.ToDictionary(pi => pi.Name, pi => pi);
			foreach (var item in xml.Elements())
			{
				PropertyInfo propertyInfo;
				if (!dict.TryGetValue(item.Name.LocalName, out propertyInfo)) continue;
				var value = DeserializeValue(item, propertyInfo.PropertyType);
				propertyInfo.SetValue(result, value, null);
			}
			return result;
		}

		private object DeserializeArray(Type targetType)
		{
			if (targetType.IsArray) // Foo[]
			{
				var elemType = targetType.GetElementType();
				dynamic array = Array.CreateInstance(elemType, xml.Elements().Count());
				var index = 0;
				foreach (var item in xml.Elements())
				{
					array[index++] = DeserializeValue(item, elemType);
				}
				return array;
			}
			else // List<Foo>
			{
				var elemType = targetType.GetGenericArguments()[0];
				dynamic list = Activator.CreateInstance(targetType);
				foreach (var item in xml.Elements())
				{
					list.Add(DeserializeValue(item, elemType));
				}
				return list;
			}
		}

		// Delete
		public override bool TryInvoke(InvokeBinder binder, object[] args, out object result)
		{
			result = (IsArray)
				? Delete((int)args[0])
				: Delete((string)args[0]);
			return true;
		}

		// IsDefined, if has args then TryGetMember
		public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
		{
			if (args.Length > 0)
			{
				result = null;
				return false;
			}

			result = IsDefined(binder.Name);
			return true;
		}

		// Deserialize or foreach(IEnumerable)
		public override bool TryConvert(ConvertBinder binder, out object result)
		{
			if (binder.Type == typeof(IEnumerable) || binder.Type == typeof(object[]))
			{
				var ie = (IsArray)
					? xml.Elements().Select(x => ToValue(x))
					: xml.Elements().Select(x => (dynamic)new KeyValuePair<string, object>(x.Name.LocalName, ToValue(x)));
				result = (binder.Type == typeof(object[])) ? ie.ToArray() : ie;
			}
			else
			{
				result = Deserialize(binder.Type);
			}
			return true;
		}

		private bool TryGet(XElement element, out object result)
		{
			if (element == null)
			{
				result = null;
				return false;
			}

			result = ToValue(element);
			return true;
		}

		public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result)
		{
			return (IsArray)
				? TryGet(xml.Elements().ElementAtOrDefault((int)indexes[0]), out result)
				: TryGet(xml.Element((string)indexes[0]), out result);
		}

		public override bool TryGetMember(GetMemberBinder binder, out object result)
		{
			return (IsArray)
				? TryGet(xml.Elements().ElementAtOrDefault(int.Parse(binder.Name)), out result)
				: TryGet(xml.Element(binder.Name), out result);
		}

		private bool TrySet(string name, object value)
		{
			var type = GetJsonType(value);
			var element = xml.Element(name);
			if (element == null)
			{
				xml.Add(new XElement(name, CreateTypeAttr(type), CreateJsonNode(value)));
			}
			else
			{
				element.Attribute("type").Value = type.ToString();
				element.ReplaceNodes(CreateJsonNode(value));
			}

			return true;
		}

		private bool TrySet(int index, object value)
		{
			var type = GetJsonType(value);
			var e = xml.Elements().ElementAtOrDefault(index);
			if (e == null)
			{
				xml.Add(new XElement("item", CreateTypeAttr(type), CreateJsonNode(value)));
			}
			else
			{
				e.Attribute("type").Value = type.ToString();
				e.ReplaceNodes(CreateJsonNode(value));
			}

			return true;
		}

		public override bool TrySetIndex(SetIndexBinder binder, object[] indexes, object value)
		{
			return (IsArray)
				? TrySet((int)indexes[0], value)
				: TrySet((string)indexes[0], value);
		}

		public override bool TrySetMember(SetMemberBinder binder, object value)
		{
			return (IsArray)
				? TrySet(int.Parse(binder.Name), value)
				: TrySet(binder.Name, value);
		}

		public override IEnumerable<string> GetDynamicMemberNames()
		{
			return (IsArray)
				? xml.Elements().Select((x, i) => i.ToString())
				: xml.Elements().Select(x => x.Name.LocalName);
		}

		/// <summary>Serialize to JsonString</summary>
		public override string ToString()
		{
			// <foo type="null"></foo> is can't serialize. replace to <foo type="null" />
			foreach (var elem in xml.Descendants().Where(x => x.Attribute("type").Value == "null"))
			{
				elem.RemoveNodes();
			}
			return CreateJsonString(new XStreamingElement("root", CreateTypeAttr(jsonType), xml.Elements()));
		}
	}
}
